Method and Apparatus for Completing Wells

ABSTRACT

An apparatus for performing electrical discharge machining within a well, may include an elongated body comprising a first end and a second end and defining an interior cavity; and at least one electrode positioned within the elongated body, wherein the apparatus is configured to be connected to a power supply that enables electrical current to be supplied to the electrode to mine material from a production casing wall inside of a wellbore.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/626,858, filed on Feb. 6, 2018, the disclosure ofwhich is incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION Field of the Invention

This disclosure relates to a method and apparatus for well completionsand, more specifically, to the use of electrical discharge machiningtechnology to more effectively and efficiently create apertures in acasing tubular positioned in wells.

Description of Related Art

Since the dawn of the Industrial Revolution, evolving human society hasrequired ever-increasing amounts of energy to meet day-to-day needs. Theubiquitous use of automobiles for transportation in many developed partsof the world, the need to heat homes and power appliances, and the needto generate sufficient electricity to power cities and small towns iscurrently straining the world's energy resources beyond what mankind isable to produce. As a result, the energy industry is constantly lookingfor new ways to more efficiently and effectively harvestenergy-producing natural resources to meet the ever-increasing demand.

Over the last sixty-five years, and particularly since the beginning ofthe twenty-first century, extracting natural gas and oil fromconventional and unconventional reservoirs has become an increasinglyattractive option for increasing energy supply. There are numerousmethods by which natural gas and oil may be extracted from undergroundreservoirs. The most basic method involves drilling a well verticallyinto the earth where a reservoir is known to exist and using equipmentand machinery well known within the industry to pump the hydrocarbon(e.g., oil or gas) out of the well and into midstream assets. But thisis inefficient, so other methods are more widely utilized.

Today, the most common and well-known method of extracting natural gasand oil from underground reservoirs is hydraulic fracturing, knowncommonly as “fracking”. Wells used to extract hydrocarbons may bedrilled vertically hundreds to thousands of feet below the land surfaceand may include horizontal or directional sections extending thousandsof feet. Fracking creates fractures within a wellbore by pumping largequantities of fluids and proppants at high pressure down the wellboreand into a target rock formation. Hydraulic fracturing fluid commonlyconsists of water, proppant (such as sand, ceramic pellets or othersmall incompressible particles) and chemical additives that, when pumpedat high pressure into the target rock formation, open and enlargefractures within the rock formation. These fractures can extend severalhundred feet away from the wellbore. The proppants help to hold open thenewly created fractures.

Once the injection process is completed, the internal pressure of therock formation causes hydrocarbons and fluid naturally occurring withinthe rock formation to return to the surface through the wellbore. Thisfluid that returns with the hydrocarbons is known as both “flowback” and“produced water” (collectively referred to hereafter as “flowback”), andmay contain the injected chemicals plus naturally occurring materialssuch as brines, metals, radionuclides, and hydrocarbons. Flowback istypically stored on site in tanks or pits, before eventually beingtreated, disposed of, or recycled. In many cases, flowback is disposedof underground. When underground disposal is not possible, flowback maybe reused or treated by a wastewater treatment facility and dischargedto surface water.

Unfortunately, there is widespread concern that flowback produced byfracking is contaminating groundwater (particularly when flowback isdisposed of by injecting it underground), presenting a potential threatboth to the environment at large and to the human beings who rely ongroundwater that may be contaminated for drinking water, cooking, andbathing. Some states, such as New York, have banned fracking despitebeing home to large natural gas reservoirs that could be accessedthrough fracking. These types of bans have created significant unrestamong many communities who see fracking and other means of hydrocarbonharvesting as a means to better the economic conditions in areas wherenatural gas and oil reservoirs are located.

When a well is drilled, initially the wellbore is nothing more than adeep, cylindrical hole cut through the earth. Without fortifying thewell, a drilling operation faces the risk that the well could collapseinward on itself. In order to prevent a well from collapsing inward onitself, wells are “cased.” The casing process involves inserting intothe well very long, very large cylinders (typically made of solidsteel). These long steel cylinders form a lining (i.e., casing) againstthe walls of the well. In order to keep the casing in place, liquidconcrete is typically pumped into the space between the well walls andthe casing. When the concrete hardens, it binds the casing to the wellwall, thus fortifying the well to prevent the well from collapsing andproviding the well operator with well control.

To permit oil and gas to enter a drilled and cased wellbore, completionequipment such as perforating guns and sleeves are used to create holesin the wellbore's casing. Perforating guns are devices that are commonlyused within the energy industry in order to facilitate the extraction ofenergy resources from the ground. Because oil and natural gas reservoirsoften span large horizontal distances, a single well may be permittedfor many square acres or even many square miles of undergroundreservoir. But it is economically inefficient and often impossible inpractice (due to legal hurdles, such as obtaining easements) for adrilling operation to drill multiple wells in order to access thehorizontal breadth of a given oil or gas reservoir.

One method of accessing a reservoir's horizontal breadth withoutdrilling multiple wells is to expand the subterranean portion of a wellin a horizontal direction. By expanding the subterranean portion of awell in a horizontal direction, oil and gas located a horizontaldistance from the location where the well was drilled can still beextracted through the well.

In order to be able to produce both conventional and unconventionalreservoirs, operators need to give points of access for the hydrocarbonsto enter the production casing string. This is accomplished by the useof perforating guns, sliding sleeves, burst disks, or other pieces ofcompletion equipment. For example, perforating guns do this by allowingfor controlled, targeted underground explosions. The controlledsubterranean explosion, which targets a specific, prechosen depth andcreates a hole in the production casing at that depth by setting off aseries of shaped charges. These shaped charges pierce the productioncasing wall, and penetrate some distance into the outlying cement andgeologic formation.

When multiple perforating guns are connected in an end-to-end manner andlowered into the same vertical hole, it is commonly known as a “string”of perforating guns. There are a variety of well-known methods in theart for lowering perforating guns into a well. When perforating guns arelowered to the desired depth, the charges are detonated.

However, perforating guns have problems. One problem is that the chargeshoused in perforating guns sometimes become displaced before they aredetonated. This often results when one perforating gun on a string isdetonated before other guns on the same string. The concussive forcefrom the initial detonation often rattles the undetonated guns on thestring, and in doing so can displace the charges therein.

Electrical discharge machining (“EDM”) is a non-traditional machiningprocess. The EDM process consists of a succession of discharges made totake place between two conductors separated from each other by a film ofnon-conducting liquid, called a dielectric. During the EDM process, aseries of timed electrical pulses cause a spark to “jump” from one ofthe conductors (the electrode) and strike the second conductor (the workpiece). When the spark strikes the work piece, it removes an amount ofmaterial from the work piece. A power supply controls the timing andintensity of the electrical charges and the movement of the electrode inrelation to the work piece.

More specifically, at the spot where the electric field between theelectrode and work piece is strongest, electrons and positive free ionsare accelerated to high velocities and rapidly form an ionized channelthat conducts electricity. At this stage current can flow and the sparkforms between the electrode and work piece. During this process a bubbleof gas develops and its pressure rises very steadily until a plasma zoneis formed. The plasma zone quickly reaches very high temperatures, inthe region of 8,000 to 12,000 degrees Centigrade. This causesinstantaneous local melting of a certain amount of the material at thesurface of the work piece. When the current is cut off, the suddenreduction in temperature causes the bubble to implode, which projectsthe melted material away from the work piece, leaving a tiny crater.

EDM allows a user to achieve tighter tolerances and better finishes in awide range of materials that are otherwise difficult or impossible tomachine with traditional processes. This makes EDM especiallywell-suited for the machining of very small and very detailed workpieces. For example, EDM is often used in conjunction with the machiningof parts for the aerospace and automotive industries, as well assurgical components.

SUMMARY OF THE INVENTION

In view of the drawbacks of fracking and perforating guns increasing thedifficulty of efficiently and effectively harvesting oil and naturalgas, there is a current need within the industry for a new method andapparatus of accessing oil and natural gas reserves that does notinherit the potential dangers of fracking or the drawbacks ofperforating guns, but that still effectively and efficiently allow adrilling operation to access and harvest underground natural gas.Therefore, the present disclosure includes using a novel apparatus andmethod for incorporating EDM technology on a large scale to extractunderground natural gas and oil reserves. The present disclosureprovides a method and apparatus for employing EDM technology during thecompletion process for harvesting underground oil and natural gas. Inaddition, the present disclosure is able to use fresh water or brinewater that has not been treated, as opposed to dielectric solution, tofacilitate the EDM process. The present disclosure employs the EDMprocess directly through the production casing wall.

In one example of the present disclosure, an apparatus for performingelectrical discharge machining within a well may include an elongatedbody comprising a first end and a second end and defining an interiorcavity; and at least one electrode positioned within the elongated body,wherein the apparatus is configured to be connected to a power supplythat enables electrical current to be supplied to the electrode to minematerial from a production casing wall inside of a wellbore.

In another example of the present disclosure, the electrode may beradially adjustable relative to the elongated body. The at least oneelectrode may include a plurality of electrodes that arecircumferentially spaced apart from one another in the elongated body.At least one centralizer may be provided within the elongated body,wherein the centralizer is configured to stabilize the elongated bodywithin the production casing. The centralizer may be radially adjustablerelative to the elongated body. The at least one centralizer may includea plurality of centralizers that are circumferentially spaced apart fromone another in the elongated body. The at least one electrode may bepositioned between a first centralizer and a second centralizer on theelongated body, wherein the first and second centralizers are configuredto stabilize the elongated body within the production casing.

In another example of the present disclosure, a system for performingelectrical discharge machining within a well may include a wellcompletion device that may include an elongated body comprising a firstend and a second end and defining an interior cavity; and at least oneelectrode positioned within the elongated body, a power supplyoperatively connected to the well completion device; and a controlsystem operatively connected to the well completion device to operatethe well completion device, wherein the apparatus is configured to beconnected to a power supply that enables electrical current to besupplied to the electrode to mine material from a production casing wallinside of a wellbore.

In another example of the present disclosure, an isolation tool may beconnected to the well completion device, wherein the isolation tool isconfigured to isolate the well completion device from debris that mayfall into the wellbore. A half-moon swivel may be connected to the wellcompletion device to stabilize the well completion device within theproduction casing. The electrode may be radially adjustable relative tothe elongated body. At least one centralizer may be provided within theelongated body, wherein the centralizer may be configured to stabilizethe elongated body within the production casing. The centralizer may beradially adjustable relative to the elongated body. The at least oneelectrode may be positioned between a first centralizer and a secondcentralizer on the elongated body, wherein the first and secondcentralizers may be configured to stabilize the elongated body withinthe production casing.

In another example of the present disclosure, a method of performingelectrical discharge machining within a well may include (a) inserting awell completion device into a production casing positioned within awellbore, the well completion tool comprising an elongated bodycomprising a first end and a second end and defining an interior cavity,and at least one electrode positioned within the elongated body; (b)bringing the at least one electrode adjacent an inner surface of theproduction casing; (c) generating an electrical spark between the atleast one electrode and the inner surface of the production casing tomine material from the production casing; (d) ceasing generation of theelectrical spark between the at least one electrode and the innersurface of the production casing; (e) washing the production casing withwater to clean the area of the production casing that is being mined;and (f) repeating steps (c)-(e) until an aperture is created within theproduction casing.

In another example of the present disclosure, the water may be freshwater or brine water. Step (b) may include extending the at least oneelectrode from the elongated body or moving the elongated body adjacentthe inner surface of the production casing. Before step (b), the methodmay include stabilizing the well completion device within the productioncasing. The well completion device may be stabilized in the productioncasing using at least one centralizer that radially extends from theelongated body. The method may include positioning an isolation tool ontop of the well completion device to prevent debris from an opening ofthe wellbore from damaging the well completion device.

The present disclosure is also defined by the following clauses.

Clause 1: An apparatus for performing electrical discharge machiningwithin a well, comprising: an elongated body comprising a first end anda second end and defining an interior cavity; and at least one electrodepositioned within the elongated body, wherein the apparatus isconfigured to be connected to a power supply that enables electricalcurrent to be supplied to the electrode to mine material from aproduction casing wall inside of a wellbore.

Clause 2: The apparatus of Clause 1, wherein the electrode is radiallyadjustable relative to the elongated body.

Clause 3: The apparatus of Clause 1 or 2, wherein the at least oneelectrode comprises a plurality of electrodes that are circumferentiallyspaced apart from one another in the elongated body.

Clause 4: The apparatus of any of Clauses 1-3, further comprising atleast one centralizer provided within the elongated body, wherein thecentralizer is configured to stabilize the elongated body within theproduction casing.

Clause 5: The apparatus of Clause 4, wherein the centralizer is radiallyadjustable relative to the elongated body.

Clause 6: The apparatus of Clause 4 or 5, wherein the at least onecentralizer comprises a plurality of centralizers that arecircumferentially spaced apart from one another in the elongated body.

Clause 7: The apparatus of any of Clauses 1-6, wherein the at least oneelectrode is positioned between a first centralizer and a secondcentralizer on the elongated body, wherein the first and secondcentralizers are configured to stabilize the elongated body within theproduction casing.

Clause 8: A system for performing electrical discharge machining withina well, comprising: a well completion device, comprising: an elongatedbody comprising a first end and a second end and defining an interiorcavity; and at least one electrode positioned within the elongated body,a power supply operatively connected to the well completion device; anda control system operatively connected to the well completion device tooperate the well completion device, wherein the apparatus is configuredto be connected to a power supply that enables electrical current to besupplied to the electrode to mine material from a production casing wallinside of a wellbore.

Clause 9: The system of Clause 8, further comprising an isolation toolconnected to the well completion device, wherein the isolation tool isconfigured to isolate the well completion device from debris that mayfall into the wellbore.

Clause 10: The system of Clause 8 or 9, further comprising a half-moonswivel connected to the well completion device to stabilize the wellcompletion device within the production casing.

Clause 11: The system of any of Clauses 8-10, wherein the electrode isradially adjustable relative to the elongated body.

Clause 12: The system of any of Clauses 8-11, further comprising atleast one centralizer provided within the elongated body, wherein thecentralizer is configured to stabilize the elongated body within theproduction casing.

Clause 13: The system of Clause 12, wherein the centralizer is radiallyadjustable relative to the elongated body.

Clause 14: The system of any of Clauses 8-13, wherein the at least oneelectrode is positioned between a first centralizer and a secondcentralizer on the elongated body, wherein the first and secondcentralizers are configured to stabilize the elongated body within theproduction casing.

Clause 15: A method of performing electrical discharge machining withina well, comprising: (a) inserting a well completion device into aproduction casing positioned within a wellbore, the well completion toolcomprising an elongated body comprising a first end and a second end anddefining an interior cavity, and at least one electrode positionedwithin the elongated body; (b) bringing the at least one electrodeadjacent an inner surface of the production casing; (c) generating anelectrical spark between the at least one electrode and the innersurface of the production casing to mine material from the productioncasing; (d) ceasing generation of the electrical spark between the atleast one electrode and the inner surface of the production casing; (e)washing the production casing with water to clean the area of theproduction casing that is being mined; and (f) repeating steps (c)-(e)until an aperture is created within the production casing.

Clause 16: The method of Clause 15, wherein the water is fresh water orbrine water.

Clause 17: The method of Clause 15 or 16, wherein step (b) comprisesextending the at least one electrode from the elongated body or movingthe elongated body adjacent the inner surface of the production casing.

Clause 18: The method of any of Clauses 15-17, further comprising,before step (b), stabilizing the well completion device within theproduction casing.

Clause 19: The method of Clause 18, wherein the well completion deviceis stabilized in the production casing using at least one centralizerthat radially extends from the elongated body.

Clause 20: The method of any of Clauses 15-19, further comprisingpositioning an isolation tool on top of the well completion device toprevent debris from an opening of the wellbore from damaging the wellcompletion device.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are not intended to in any way limit thescope of the invention disclosed herein. The drawings are merelyincluded to clarify and exemplify the invention as disclosed and claimedherein.

FIG. 1 is a perspective view of a well completion device according toone example of the present disclosure;

FIG. 2 is another perspective view of the well completion device shownin FIG. 1;

FIG. 3 is a side view of the well completion device shown in FIG. 1;

FIG. 4 is a cross-sectional view of the well completion device shown inFIG. 1;

FIG. 5 is a schematic illustration of a well completion system includingthe well completion device shown in FIG. 1;

FIG. 6 is a perspective view of an electrode arrangement provided in thewell completion device shown in FIG. 1;

FIG. 7 is a perspective view of a control system/controller used inconjunction with the well completion device shown in FIG. 1; and

FIG. 8 is a perspective view of an information input panel provided onthe control system/controller shown in FIG. 7.

DESCRIPTION OF THE INVENTION

The following description is provided to enable those skilled in the artto make and use the described embodiments contemplated for carrying outthe invention. Various modifications, equivalents, variations, andalternatives, however, will remain readily apparent to those skilled inthe art. Any and all such modifications, variations, equivalents, andalternatives are intended to fall within the spirit and scope of thepresent invention.

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”,“longitudinal”, and derivatives thereof shall relate to the invention asit is oriented in the drawing figures. However, it is to be understoodthat the invention may assume various alternative variations, exceptwhere expressly specified to the contrary. It is also to be understoodthat the specific devices illustrated in the attached drawings, anddescribed in the following specification, are simply exemplaryembodiments of the invention. Hence, specific dimensions and otherphysical characteristics related to the embodiments disclosed herein arenot to be considered as limiting.

With reference to FIGS. 1-8, the present disclosure is directed to amethod and apparatus for well completions and, more specifically, to theuse of electrical discharge machining (EDM) technology to moreeffectively and efficiently create apertures in a casing tubularpositioned in wells. While the following disclosure describes a methodof using EDM technology with the well completion device 2, it is alsocontemplated that other methods of machining may be used with the wellcompletion device 2, including a cutting torch, combustion machining,laser machining, and mechanical machining methods.

With reference to FIGS. 1-3, the well completion device 2 includes anelongated body 4. The elongated body 4 may be made from any materialthat is suitable for withstanding the pressures and temperatures withinunderground wells and the stress that is created as a result of the EDMprocess. In one example of the present disclosure, the elongated body 4is made of high-strength stainless steel. The elongated body 4 may havea generally cylindrical shape, but it is contemplated that anyadditional shapes may be used as needed according to the shape of thewell in which the well completion device 2 is to be used. The elongatedbody 4 may be a monolithic structure or, in an alternative example, maybe modular and include several different segments that are operativelyconnected or formed with one another. In one example, the separatesegments may be welded together, adhesively attached to one another,and/or mechanically connected to one another to form the elongated body4. It is also contemplated that the length of the elongated body 4 mayvary based on the size of the well and the desired number of aperturesthat are to be formed in the production casing in the well, as will bedescribed in greater detail below. The elongated body includes a firstend 6 and an opposing second end 8. When inserted into a well, thesecond end 8 of the elongated body 4 is inserted into the well firstsuch that the second end is provided at a deeper position within thewell than the first end 6. The elongated body 4 defines an internalcavity that houses several different components used to operate the wellcompletion device 2, as will be described below in greater detail.

In one example of the present disclosure, provided within or as part ofthe elongated body 4 is at least one electrode 10. In one example, aplurality of electrode 10 groupings are provided along a longitudinallength of the elongated body 4. In one example, at least one electrode10 grouping is provided along the length of the elongated body 4. Theelectrode 10 grouping may include at least four electrodes 10 that arecircumferentially spaced from one another about the longitudinal axis Aof the elongated body 4. In one example, the electrodes 10 of theelectrode grouping are equally spaced from one another. It is to beunderstood, however, that additional or less electrodes 10 may beprovided in the electrode 10 grouping and the electrodes 10 may bespaced from one another at any number of different angles or spacinglengths. The electrode(s) 10 are responsible for producing an electricspark that, as explained herein, penetrates a wellbore production casingand bores fissures or holes within the well wall (horizontal orotherwise). As will be described below, in order to provide the energynecessary to produce the electric spark with the electrode(s) 10, thewell completion device 2 is connected to a power supply that channelselectric current from the energy source to the well completion device 2.Those with skill in the art will recognize that there are numerousenergy sources that may be used to provide sufficient electricity to thewell completion device 2 and any such energy source should be consideredsufficient.

In one example, the electrode(s) 10 may be radially adjustable relativeto the elongated body 4. For example, the electrode(s) 10 may movebetween a position in which the electrode(s) 10 is housed within theelongated body 4 and a position in which the electrode(s) 10 is radiallyextended from the elongated housing 4. The electrode(s) 10 can beextended to a plurality of different lengths from the elongated body 4such that the well completion device 2 can be used with variousproduction casings and wellbores of different sizes. As shown in FIG. 6,a servo motor gear 60 may be provided in the well completion device 2that is in operative connection with a servo motor, also housed in thewell completion device 2. The servo motor gear 60 may be operativelyengaged with an internal gear 62 defined in the section of the elongatedbody 4 in which the electrode(s) 10 are positioned. During operation, asthe servo motor rotates the servo motor gear 60, the internal gear 62 isrotated, thereby causing a Geneva gear (or cam surface) 64 provided inthe elongated housing 4 to rotate towards and contact a bearing member66 positioned on the electrode(s) 10. As the Geneva gear 64 is rotated,the bearing member 66 is also rotated outwardly to move the electrode(s)10 in a radially outward direction to extend from the elongated body 4.To retract the electrode(s) 10 back into the elongated body 4, the servomotor is configured to rotate the servo motor gear 60 in an oppositedirection to reverse the direction that the internal gear 62 is rotated.The electrode(s) 10 may be extended to create an electric spark with theproduction casing wall. In one example, the electrode(s) 10 may berotatable about the longitudinal axis A of the elongated body 4. Acontroller may be operatively connected to the well completion device 2to move the electrode(s) 10 to desired positions within the productioncasing to create apertures in the production casing. The controller mayinclude specific programs so that the electrode(s) 10 are extended androtated according to a predetermined pattern to ensure the apertures arecreated in the production casing at desired positions. In one example,the electrode(s) 10 may be extended at a first position to createapertures in the production casing and, subsequently, the electrode(s)10 may be rotated to a different second position to create a second setof apertures in the production casing.

The present disclosure may also optionally include an electrode(s) 10that rotates as part of the well completion device 2. Enabling theelectrode(s) 10 to rotate enables the well completion device 2 to minean area of the production casing, then rotate the electrode(s) 10 andmine a different area of the production casing, without having to rotateor otherwise alter the position of the elongated body 4 itself. Thisprovides a significant advantage to users since altering the position ofthe entire well completion device 2 can be a time-consuming process thatreduces the efficiency of an oil and gas mining operation. Increasingthe efficiency of the process by including a rotating electrode(s) 10,therefore, provides a user of the present disclosure an advantage in themarketplace.

The user of the present invention can vary the size of the spark, andtherefore the amount of the work piece mined away from any single spark,by varying the size of the tool.

Those with skill in the art will recognize how to manufacture the toolsuch that the production casing wall can be mined in an efficient,effective manner. The optimal size and intensity of the spark will varybased on the user's need.

With continued reference to FIGS. 1-3, the well completion tool 2 mayalso include at least one centralizer 12 provided in the elongated body4. In another example, a plurality of centralizers 12 may be provided ina circumferential pattern around the outer surface of the elongated body4. It is also contemplated that multiple groups of centralizers 12 maybe spaced along the longitudinal length of the elongated body 4 toassist in further stabilizing the well completion device 2 within theproduction casing. Similar to the electrode(s) 10, the centralizer 12 isradially adjustable relative to the longitudinal axis A of the elongatedbody 4. In one example, the centralizer 12 can move between a firstposition in which the centralizer 12 is housed within the elongatedhousing 4 and a second position in which the centralizer 12 is extendedfrom the elongated housing 4. The centralizer 12 can be extended to aplurality of different lengths from the elongated body 4 such that thewell completion tool 2 can be used with various production casings andwellbores of different sizes. The centralizer 12 is configured to extendradially outward from the elongated housing 4 to contact the innersurface of the production casing to stabilizing the well completiondevice 2 therein. In one example, the centralizers 12 are configured toextend and retract from the elongated housing 4 using a similarconfiguration to the electrode arrangement shown in FIG. 6. Thecentralizer 12 is configured to press against the inner surface of theproduction casing so that the well completion device 2 cannot rotate orwobble within the production casing while the electrode(s) 10 create theholes in the production casing. The outer end of the centralizer 12 mayinclude a gripping material, such as rubber, to assist in gripping theproduction casing. It is also contemplated that other gripping materialsmay be used to assist the centralizer 12 in contacting and creating ahold on the production casing.

As shown in FIG. 1, the well completion device 2 also includes a wirerope 14 operatively connected to the first end 6 of the elongatedhousing 4. In another example of the present disclosure, a coil tubingmay be used to suspend the end of the wire rope 14 and the wellcompletion device 2 to control the location of the well completiondevice 2 within the wellbore. The coil tubing and the wire rope 14 areused to move the well completion device 2 into and out of the productioncasing and wellbore. The well completion device 2 may also include aninput cable 16 operatively connected to the first end of the elongatedhousing 4. As will be described in greater detail below, the input cable16 provides power to the well completion device 2, as well as provides acommunication link between the well completion device 2 and a controlsystem/controller provided on the surface.

With reference to FIG. 4, the internal components of the well completiondevice 2 are briefly described and illustrated. In one example, a gatedrive printed circuit board (PCB) 18, a CPU board 20, a detection/reversboard 22, a power regulator board 24, and a fiber optic module 26 areprovided within an interior cavity of the elongated housing 4. The wellcompletion device 2 also includes a grip motor 28, 30 for eachcentralizer 12 to enable the centralizer 12 to be radially movedrelative to the elongated body 4. The well completion device 2 alsoincludes an electrode motor drive 32 used to radially move theelectrode(s) 10 relative to the elongated housing 4. The fiber opticmodule controls the status of the devices in the ground from the groundsurface (e.g., input of processing conditions, foot control, electrodeup/down control, etc.). In one example, the fiber optic module 26 may bean optical communication device for sending and receiving control andfeed back in real time. The CPU board 20 may be configured to send thedata received from control system/controller 50 provided on the groundsurface to each component of the well completion device 2. In oneexample, the detection/revers board 22 may be configured to check themotor current of the well completion device 2 to determine whether thefoot is spreading inside of the production casing, to detect the motorcurrent periodically, and to supply a stable discharge power. In oneexample, the power regulator board 24 may be configured to control astable control power in the well completion device 2 due to voltagedrops that occur when the length of the power supplied to the wellcompletion device 2 from the ground surface is increased.

With reference to FIG. 5, a well completion system 32 is shown anddescribed. In one example, the well completion system 32 includes thewell completion device 2, a half-moon swivel 34, an isolation tool 36,and a coil tubing string 38. In one example, the well completion system32 is positioned in a production casing 40 that has been inserted into apre-formed wellbore 42. In one example, the production casing 40 may bea steel pipe. In another example, the production casing 40 may be afiberglass, stainless steel, or any other type of metal pipe. It is tobe understood that the production casing 40 may be any tubular orstructural piece that is installed with the purpose of controllingproduction flow from a well. In one example, the half-moon swivel 34 isprovided at a deepest or foremost position within the wellbore 42, whilethe coil tubing string 38 is positioned nearest the surface 44. Each ofthe well completion device 2, a half-moon swivel 34, an isolation tool36, and a coil tubing string 38 may be operatively connected to oneanother to form the well completion system 32.

The half-moon swivel 34 may be provided to keep the well completiondevice 2 centralized within the production casing 40. The half-moonswivel 34 extends outwardly to make contact with the inner surface ofthe production casing 40 to stabilize the well completion device 2within the interior cavity of the production casing 40. By using thehalf-moon swivel 34 as a stabilizing element, the well completion device2 does not need to strain under pressure while creating apertures in theproduction casing 40. In one example, a shock absorbing member (notshown) may be incorporated into the half-moon swivel 34 to eliminate orminimize any vibrations in the half-moon swivel 34 and/or the wellcompletion device 2. It is also contemplated that the half-moon swivel34 may be provided with any circular pattern, provided the half-moonswivel 34 maintains an outer diameter that is close to the designatedproduction casing inner diameter. The well completion system 32 may alsoinclude the isolation tool 36 to isolate the well completion device 2from elements upstream or above the well completion device 2. Theisolation tool 36 may include at least one rubber or gripping materialmember 46 that contacts and engages the inner surface of the productioncasing 40 to stabilize the well completion device 2 therein. It is alsocontemplated that the isolation tool 36 may operate as a sealing elementduring stimulation efforts in the down hole. In one example, an internalmandrel positioned within the isolation tool 36 is provided to swell theisolation tool 36 to press against the inner surface of the productioncasing 40. After use, the internal mandrel may be retracted to reducethe outer diameter of the isolation tool 36 to disengage from contactwith the inner surface of the production casing 40. This method may becontinuously used so that the isolation tool 36 may be repeatedly usedwithin the production casing 40. The isolation tool 36 may also beprovided to ensure that the working fluid used in conjunction with theelectrode(s) 10 is directed to the desired area within the well bore. Itis contemplated that a plurality of rubber or gripping material membersmay be provided on the isolation tool 36 to increase the grippingcapabilities of the isolation tool 36 with the production casing 40. Thecoil tubing string 38 is provided to give protection to the input cable16 to prevent the input cable 16 from being damaged by any outsideelements or elements within the production casing 40.

As shown in FIG. 5, the well completion system 32 may be operativelyconnected to a power supply 48 and a control system/controller 50. Thepower supply 48 provides power to the well completion device 2 to allowthe well completion device 2 to control the electrode(s) 10 and thecentralizers 12. In some examples of the present disclosure, the powersupply 48 may be a generator, a battery, a mud motor, natural gas fire,and any other suitable method for providing power to the well completiondevice 2. The control system/controller 50 is provided to control theoperation of the well completion device 2. As shown in FIGS. 7 and 8,the control system/controller 50 may include a power switch 80 tocontrol when power is applied to the well completion system 32. Anemergency stop button 82 is also provided on the controlsystem/controller 50 to allow a user to immediately power down the wellcompletion system 32 in the event of an emergency. A bar meter 84 isprovided on the control system/controller 50 to indicate to a user whenthe EDM processing is being implemented in the ground. An informationinput panel 86 is also provided on the control system/controller 50 toallow the user to operate the well completion system 32 and receiveinformation regarding the operating performance of the well completionsystem 32. As shown in FIG. 8, the information input panel 86 mayinclude EDM condition sensors 88 that indicate to a user the currentoperating status of the well completion device 2. A down hole counter 90may be provided to indicate to a user the current down hole in which thewell completion device 2 is operating, in the event multiple down holeshave been drilled and multiple well completion devices 2 have beeninserted into the different down holes. The information input panel 86may also include buttons 92 that permit a user to change the operatingcondition/status of the well completion device 2. Lastly, theinformation input panel 86 may include an EDM processing depth indicator94 to indicate to a user the depth at which the well completion device 2is operating with inside of the ground.

In one example of the present disclosure, it is contemplated thatmultiple well completion devices 2 may be chained or connected to oneanother depending on the size and depth of the wellbore 42 in which theproduction casing 40 is positioned. Therefore, in the event the wellbore42 is particularly deep, at least two well production devices 2 may beoperatively connected to one another to create apertures along theentire length of the production casing 40 in the wellbore 42. It is alsocontemplated that an isolation tool 36 may be provided between each wellcompletion device 2 on the chain of multiple well completion devices 2.

The operation and use of the well completion device 2 will now bedescribed in greater detail. Initially, the wellbore 42 is formed in theearth and a production casing 40 is positioned therein. After theproduction casing 40 has been inserted into the wellbore 42, the wellcompletion device 2 is moved into position with in an interior cavity ofthe production casing 40. The centralizers 12 are then operated toextend from the elongated housing 4 of the well completion device 2. Thecentralizers 12 push against and contact the inner surface of theproduction casing 40 to stabilize the well completion device 2 withinthe production casing 40. Once the well completion device 2 has beenstabilized within the production casing 40, the electrode(s) 10 areextended from the elongated housing 4 to create apertures or holeswithin the production casing 40. In traditional EDM, a second electrode(the “work piece”) would be present, and it would be the differential incurrent between the work piece and the tool that creates the spark thatwould mine material from the work piece. In the present disclosure,however, the production casing 40 functions as the “work piece”electrode.

The well completion device 2 should preferably be manufactured such thatit can conduct sufficient electricity to produce a spark of sufficientenergy and heat to mine the production casing 40. Different materialsfrom which the electrode(s) 10 can be manufactured will enable theelectrode(s) 10 to conduct different maximum amperages, therebyproducing sparks of different maximum intensities and heats. Amperage inthe range of 50 to 150 amps will enable the present disclosure tofunction in an intended manner, but other amperages (higher and lower)may be utilized depending on the material from which the electrode(s) 10is manufactured and the material of the production casing 40 that mustbe mined away. In a preferred embodiment, the electrode(s) 10 includedwith the elongated body 4 may be manufactured from copper, brass, orgraphite.

In traditional EDM, the work piece is held still and the tool iscontinuously moved closer to the work piece until the spark occurs,mining material from the work piece. Once the spark occurs, the tool istemporarily moved away from the work piece and/or the power istemporarily cut from the electrode, and the work piece is then washedwith dielectric fluid. Thereafter, the tool is again moved close to thework piece and/or power is restored to the electrode until the electrodeagain sparks. This process is referred to herein as a “cycle” and, intraditional EDM, a cycle occurs so rapidly that it appears to the nakedeye that the spark is continuously mining material from the work piece.

For the present disclosure, the electrode(s) 10 of the well completiondevice 2, connected to the power supply 48, must be moved close to theproduction casing 40 until a spark occurs that mines away a portion ofthe production casing 40. Once the spark occurs, the electrode(s) 10 istemporarily moved away from the production casing 40 and the area of theproduction casing 40 where the spark mined away material is washed withfresh water or brine water. The fresh water or brine water may bedirected through an annulus of the coil tubing string 38 and out from aported sleeve positioned on top of the well completion device 2. Inanother example, the fresh water or brine water may be pumped outside ofthe coil tubing string 38 and past the well completion device 2.Alternatively, the electrode(s) 10 may be kept in place and the powersupply 48 may temporarily cease providing electrical current to theelectrode(s) while the mined material is washed away with fresh or brinewater. In yet another example, the electrode(s) 10 may be moved awayfrom the production casing 40 and the power supply 48 may temporarilycease providing power to the electrode(s) 10 while the mined material iswashed away with fresh or brine water. In another example of the presentdisclosure, instead of extending and retracting the electrode(s), thewell completion tool 2 itself may be moved towards and away from theproduction casing 40 to mine material from the production casing 40. Inone example, the well completion tool 2 is moved towards and away fromthe production casing 40 by using the centralizer 12 to push or pull thewell completion device 2 in different directions within the productioncasing 40.

The apparatus and method of the present disclosure (and set forth morefully below) may use fresh water or brine water as opposed to dielectricfluid as is used in traditional EDM processes. In traditional EDM,dielectric is used because it enables the traditional EDM process toobtain the tight tolerances that allow for very detailed machining ofsmall parts. But in using the well completion device 2 disclosed hereinaccording to the method disclosed herein, tight tolerances are notnecessary. Instead, the present well completion device 2 and method arefocused on ensuring that the production casing 40 and well wall that isbeneath the casing are mined to create fissures that enable access tohydrocarbons adjacent to the drilled well. Once the mined area of theproduction casing 40 is washed, the electrode(s) 10 may again be movedclose to the production casing 40 and/or (as needed) the power supply 48may again supply power to the electrode(s) until the spark again occursto mine away a portion of the production casing 40. This constitutes a“cycle” of the present disclosure.

The present disclosure may optionally use multiple electrodes 10 thatare machining the production casing 40 simultaneously. This will reducethe amount of time needed to reposition the well completion device 2 ina different position within the production casing 40, which will allowthe efficiency and effectiveness of the process to be advantageous overexisting methods of perforating, sleeve systems, and other pieces ofcompletion equipment.

The present disclosure may also include additional elementstraditionally found in well completion systems. For instance, theelongated body 4 may include an end cap and a capsule guard. Byincluding such elements, the well completion device 2 is able tofunction more effectively within the environment found in undergroundwells.

The present disclosure includes a novel method of EDM. In particular,the method of the EDM process disclosed herein is novel in that theinside production casing wall is the work piece and the work piece iswashed with fresh water or brine water, as opposed to dielectric fluid.Machining a tubular work piece from the inside out has not yet beenperformed in the current art. Utilizing the present invention andmethod, the well completion device 2 may be lowered into a tubularwithout installing any permanent or semi-permanent housing. The wellcompletion device 2 of the present disclosure is thus an “independent”apparatus that may be utilized in any well without the need to installadditional housing or machinery to enable the tool's use. Furthermore,being able to use fresh water or brine water instead of dielectric fluidresults in the EDM method disclosed herein being faster and cheaper,which is a significant advantage within the industry. Extracting oil andnatural gas from underground reserves is a very expensive process.Enabling users of the present invention and method disclosed herein tosave time and money in the process of extracting oil and natural gasfrom underground reserves will provide users of the present inventionand method a competitive advantage in the marketplace. It is alsocontemplated that this novel method may be used in non-oil and gasapplications to create apertures or holes in a casing.

While this disclosure has been described as having exemplary designs,the present disclosure can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the disclosure using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains and which fallwithin the limits of the appended claims.

The invention claimed is:
 1. An apparatus for performing electricaldischarge machining within a well, comprising: an elongated bodycomprising a first end and a second end and defining an interior cavity;and at least one electrode positioned within the elongated body, whereinthe apparatus is configured to be connected to a power supply thatenables electrical current to be supplied to the electrode to minematerial from a production casing wall inside of a wellbore.
 2. Theapparatus of claim 1, wherein the electrode is radially adjustablerelative to the elongated body.
 3. The apparatus of claim 1, wherein theat least one electrode comprises a plurality of electrodes that arecircumferentially spaced apart from one another in the elongated body.4. The apparatus of claim 1, further comprising at least one centralizerprovided within the elongated body, wherein the centralizer isconfigured to stabilize the elongated body within the production casing.5. The apparatus of claim 4, wherein the centralizer is radiallyadjustable relative to the elongated body.
 6. The apparatus of claim 4,wherein the at least one centralizer comprises a plurality ofcentralizers that are circumferentially spaced apart from one another inthe elongated body.
 7. The apparatus of claim 1, wherein the at leastone electrode is positioned between a first centralizer and a secondcentralizer on the elongated body, wherein the first and secondcentralizers are configured to stabilize the elongated body within theproduction casing.
 8. A system for performing electrical dischargemachining within a well, comprising: a well completion device,comprising: an elongated body comprising a first end and a second endand defining an interior cavity; and at least one electrode positionedwithin the elongated body, a power supply operatively connected to thewell completion device; and a control system operatively connected tothe well completion device to operate the well completion device,wherein the apparatus is configured to be connected to a power supplythat enables electrical current to be supplied to the electrode to minematerial from a production casing wall inside of a wellbore.
 9. Thesystem of claim 8, further comprising an isolation tool connected to thewell completion device, wherein the isolation tool is configured toisolate the well completion device from debris that may fall into thewellbore.
 10. The system of claim 8, further comprising a half-moonswivel connected to the well completion device to stabilize the wellcompletion device within the production casing.
 11. The system of claim8, wherein the electrode is radially adjustable relative to theelongated body.
 12. The system of claim 8, further comprising at leastone centralizer provided within the elongated body, wherein thecentralizer is configured to stabilize the elongated body within theproduction casing.
 13. The system of claim 12, wherein the centralizeris radially adjustable relative to the elongated body.
 14. The system ofclaim 8, wherein the at least one electrode is positioned between afirst centralizer and a second centralizer on the elongated body,wherein the first and second centralizers are configured to stabilizethe elongated body within the production casing.
 15. A method ofperforming electrical discharge machining within a well, comprising: (a)inserting a well completion device into a production casing positionedwithin a wellbore, the well completion tool comprising an elongated bodycomprising a first end and a second end and defining an interior cavity,and at least one electrode positioned within the elongated body; (b)bringing the at least one electrode adjacent an inner surface of theproduction casing; (c) generating an electrical spark between the atleast one electrode and the inner surface of the production casing tomine material from the production casing; (d) ceasing generation of theelectrical spark between the at least one electrode and the innersurface of the production casing; (e) washing the production casing withwater to clean the area of the production casing that is being mined;and (f) repeating steps (c)-(e) until an aperture is created within theproduction casing.
 16. The method of claim 15, wherein the water isfresh water or brine water.
 17. The method of claim 15, wherein step (b)comprises extending the at least one electrode from the elongated bodyor moving the elongated body adjacent the inner surface of theproduction casing.
 18. The method of claim 15, further comprising,before step (b), stabilizing the well completion device within theproduction casing.
 19. The method of claim 18, wherein the wellcompletion device is stabilized in the production casing using at leastone centralizer that radially extends from the elongated body.
 20. Themethod of claim 15, further comprising positioning an isolation tool ontop of the well completion device to prevent debris from an opening ofthe wellbore from damaging the well completion device.